Ameresco, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Debt and Financing Lease Liabilities - Senior Secured Credit Facility - Revolver and Term Loan (Details)

Debt and Financing Lease Liabilities - Senior Secured Credit Facility - Revolver and Term Loan (Details)					1 Months Ended		12 Months Ended
	Jul. 27, 2025	Jul. 27, 2021 USD ($)	Jun. 22, 2021 USD ($) bank	Feb. 29, 2020	Feb. 28, 2021 USD ($)	Mar. 31, 2020	Dec. 31, 2021 USD ($)	Jun. 21, 2021 USD ($)	Mar. 31, 2021	Dec. 31, 2020 USD ($)	Oct. 31, 2020 USD ($)	Oct. 01, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 28, 2019 USD ($) bank	Jun. 27, 2019 USD ($)
Line of Credit Facility [Line Items]
Total funded debt to EBITDA covenant ratio, maximum			3.50					3.25
Letters of credit outstanding							$ 13,824,000
Line of credit							$ 97,401,000			$ 110,270,000
Term of payments required in debt service reserve							6 months
Balance of term notes							$ 37,263,000
Make-whole Provision
Line of Credit Facility [Line Items]
Derivative liability, notional amount							5,164,000
Eurocurrency Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.00%
Term Loan \| Notes payable to banks
Line of Credit Facility [Line Items]
Original principal amount															$ 65,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee percentage			0.375%
Periodic principal payment			$ 1,219,000
Maximum amount of company's consolidated stockholders' equity eligible for investment in or loan to non-core subsidiaries			0.49
Minimum debt service coverage ratio			1.5
Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Current borrowing capacity			$ 20,000,000
Additional borrowing capacity (up to)			100,000,000
Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Additional borrowing capacity (up to)			$ 25,000,000
Revolving Credit Facility \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.50%
Revolving Credit Facility \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.25%
Revolving Credit Facility \| Federal Funds Effective Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.50%
Revolving Credit Facility \| London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.50%
Revolving Credit Facility \| London Interbank Offered Rate (LIBOR) \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate			2.00%
Revolving Credit Facility \| London Interbank Offered Rate (LIBOR) \| Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.75%
Line of Credit \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, number of banks \| bank			3												3
Total funded debt to EBITDA covenant ratio, maximum						3.75			3.25
Line of credit facility, additional borrowing capacity			$ 65,000,000
Maximum borrowing capacity		$ 60,000,000						$ 115,000,000							$ 185,000,000	$ 125,000,000
Current borrowing capacity			180,000,000
Unamortized discount			$ 78,000
Remaining borrowing capacity							121,176,000
Line of credit							$ 44,681,000			$ 52,696,000
Stated interest rate (percent)							3.50%
Line of Credit \| Revolving Credit Facility \| October 2020 Term Loan Modification
Line of Credit Facility [Line Items]
Line of credit facility, additional borrowing capacity					$ 15,000,000
Maximum borrowing capacity											$ 50,000,000	$ 35,000,000	$ 28,500,000
Unamortized discount							$ 150,000
Net proceeds							14,848,000
Principal payment							1,250,000
Debt instrument, fee amount							2,000
Line of credit							38,016,000
Line of Credit, Option To Increase Limit, Amount											$ 15,000,000
Line of Credit \| Revolving Credit Facility \| June 2020 Construction Revolver
Line of Credit Facility [Line Items]
Maximum borrowing capacity														$ 100,000,000
Remaining borrowing capacity							76,065,000
Line of credit							23,792,000
Line of Credit \| Revolving Credit Facility \| July 2020 Construction Revolver
Line of Credit Facility [Line Items]
Remaining borrowing capacity							22,237,000
Line of credit							$ 7,638,000
Line of Credit \| Revolving Credit Facility \| Eurocurrency Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.00%	0.00%		1.00%
Secured Debt
Line of Credit Facility [Line Items]
Original principal amount		$ 44,748,000
Stated interest rate (percent)		3.25%
Debt service coverage ratio							1.2
Lender fees and debt issuance costs							$ 957,000
Secured Debt \| Term Loan Due March 2046
Line of Credit Facility [Line Items]
Original principal amount		$ 40,683,000
Secured Debt \| Term Loan Due March 2030
Line of Credit Facility [Line Items]
Original principal amount		$ 4,065,000
Secured Debt \| London Interbank Offered Rate (LIBOR) \| Term Loan Due March 2030
Line of Credit Facility [Line Items]
Basis spread on variable rate		3.50%
Secured Debt \| London Interbank Offered Rate (LIBOR) \| Term Loan Due March 2030 \| Forecast
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.75%